Which of the following would be currently taxable as ordinary income to a partner if received in exchange for services performed by the partner for the partnership? (In all cases, assume the interest is not sold within two years after the time it is granted to the service partner.)

a. A 10% interest in the capital of the partnership that will not vest until a later year when the services are performed.

b. A 20% interest in the future profits of the partnership received in exchange for future services to be performed for the partnership, where the interest vests immediately.

c. A 25% interest in the future profits of the partnership, where there is no substantial risk of forfeiture.

d. Income is realized by the partner in (b) and (c), but not (a).

e. No currently taxable income will be recognized in (a), (b) or (c).